Hibernation Patterns of Dwarf Lemurs in the High Altitude Forest of Eastern Madagascar

Abstract

The dwarf lemurs of Madagascar (genus Cheirogaleus) are the only obligatory hibernators within the order Primates. Today, hibernation is used by dwarf lemur species in a variety of forest habitats, from dry deciduous, littoral to rainforest, although its expression varies within and between species. We collected data on Cheirogaleus sibreei and C. crossleyi, two eastern dwarf lemur species found at Tsinjoarivo, one of the last remaining high altitude rainforests of Madagascar. Although Crossley’s dwarf lemurs are also found in low altitude rainforests, Sibree’s dwarf lemurs appear to be high altitude specialists and are only known from Tsinjoarivo. On the basis of hibernation and other biological data collected at Tsinjoarivo for Sibree’s and Crossley’s dwarf lemurs as well as data culled from the literature on Crossley’s dwarf lemurs, fat-tailed dwarf lemurs (C. medius), and greater dwarf lemurs (C. major), we ask whether altitude affects hibernation patterns and other biological variables. We propose that hibernation evolved in the highlands of Madagascar in concurrence with severe climatic changes. Lower ambient daytime temperatures in high-altitude environments may have increased the selective premium on fattening efficiency, which may have served, in turn, as a precondition for the evolution of obligatory hibernation. Hibernation should be selectively advantageous for individuals living in cold environments, particularly if their favored resources exhibit seasonality.